1. Field of the Invention
This invention is concerned with the guiding of the movable apron or table of a machine tool intended for shaping, bending or shearing sheet metal stock.
2. Description of the Prior Art
At present this guiding action is provided for either by slideways disposed in the end portions of the movable apron or by means of sets of rollers or bearings disposed on either side of the movable apron, one portion of each set being operative for guiding the apron across its main surface and the other portion for guiding the apron laterally.
As a rule, no problem arises from the rollers or bearings disposed for guiding the apron across its major surface, for the efforts and loads developed in this direction are relatively moderate. In contrast thereto, the guide rollers or bearings operating laterally must be dimensioned to withstand high stresses and loads under overhanging conditions, and furthermore they must be as long as possible. Moreover, the length of the races engaged by these rollers or bearings should be slightly greater than the apron stroke. This requirements increases considerably the overall dimensions of the assembly.
Therefore, the present invention is directed to guiding systems of the type wherein independent rollers are interposed between the vertical races carried by the movable apron and the frame structure of the machine, respectively. Systems of this character provide a relatively substantial useful width for guiding the apron, while having a reduced volume. However, in hitherto known systems of this type considerable plays are usually observed which are detrimental to the quality of the guiding action thus obtained. Besides, mounting of the guide rollers is generally unsatisfactory.